THE fighting is finally over for the singing offspring of the late, great Hank Williams. His illegitimate daughter, Cathy Yvonne Stone, who performs under the name Jett Williams, has reached an out-of-court settlement in her eight-year battle for a share of the country legend's multi-million-dollar songwriting royalties. ''Thank God it's settled, that's what Hank said when I told him,'' Hank Williams Junior's manager, Merle Kilgore, said on Thursday. Stone's lawyer and husband, Keith Adkinson, breathed a sigh of relief over the undisclosed settlement. ''I think she's numb, to be honest, because she's been through so much for so long,'' he said. ''I think it's safe to say all parties are happy with the resolution.'' Hank Williams Senior died in 1953, five days before his daughter was born. The Alabama Supreme Court ruled in 1989 that she was defrauded in the 1960s when the estate was divided.